This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A268949 #4 Feb 16 2016 08:21:57
%S A268949 1,3,175,23611,5179791,1583828620,621893381187,298289430051783,
%T A268949 169027530016448143,110485582196129404780,81829925127960010076736
%N A268949 Number of sequences in {1,...,2n}^(2n) with longest increasing subsequence of length n.
%F A268949 a(n) = A245667(2n,n).
%e A268949 a(1) = 3: 11, 21, 22.
%e A268949 a(2) = 175: 1112, 1113, 1114, 1121, ..., 4414, 4423, 4424, 4434.
%Y A268949 Cf. A245667.
%K A268949 nonn
%O A268949 0,2
%A A268949 _Alois P. Heinz_, Feb 16 2016